Fabric structures are commonly used to enclose sports facilities such as tennis courts. These structures allow year round use of the sports facility.
In the prior art, when it was desired to partition off areas within the fabric structure, it was necessary to erect posts from which to hang dividing curtains or nets. Similarly, when lighting or scoreboards were required, the lights or scoreboards also had to be mounted on posts. However, these posts proved to be inconvenient and potentially hazardous in that they hindered the free movement of the athletes using the facility. Further, in the case of inflated structures, if the structure deflated the posts could puncture the fabric.
Attempts have been made to suspend curtains, nets, lights or the like directly from the fabric in fabric structures, and specifically from the fabric in inflated structures.
With specific reference to ceiling suspension devices used in inflated structures, one system uses a rigid disc, which is typically made of either plywood or metal, as a bearing plate on the outside of the structure from which to suspend the curtains, nets, lights or the like. A length of rope having a large nut or similar obstructing item at one end, is fed through a hole in the disc and through a corresponding hole cut into the fabric of the inflated structure.
In one variant of this system the disc is covered with a vinyl or other fabric covering and merely placed over the hole in the fabric of the inflated structure. Such a system is employed by DAFT.TM. Electrical Supplies and Services, Inc. of Mamaroneck, N.Y. in their HANG LITE.TM. suspended lighting system.
In another variant of this system, once the rope is fed through both the hole in the disc and the hole in the inflated structure, so that the disc lays flush against the outer surface of the structure, a fabric patch is applied over the disc and sealed to the fabric of the structure. The seal and patch prevent water incursion from the outside of the structure. The large nut or similar obstructing item prevents the rope from pulling through the hole in the disc. The disc thus acts as a bearing plate to support the rope and to distribute the load when a force, such as from suspending lights, is applied to the rope.
This system has a distinct disadvantage. Because the rigid disc is free to move (in the second variant movement is within the confines of the fabric patch), and because the inflated fabric structure sways in the wind, relative abrasive movement occurs between the rope and the edges of the hole cut in the fabric of the structure. This relative abrasive movement results in the rope sawing into the fabric of the structure. Consequently, the fabric structure must be occasionally repaired.
The second variant has a distinct disadvantage in that the fabric patch inflates due to the pressurized air within the inflated structure leaking through the hole in the disc and structure. This gives the fabric patch the appearance of a blister. Also, the air within the blister is often moist so that when the air in the blister cools, condensation is formed within the blister. Water condensing in the blister trickles down the rope and forms a puddle on the ground beneath. Such puddles are not only a nuisance, but also a potential hazard if the structure is being used to cover a sports facility. Further, when the structure is deflated for storage, the blister must be cut open to remove the disc. Consequently, a new patch must be installed when the structure is re-inflated.
A second system has been tried in an attempt to eliminate the use of the fabric patch. Two rigid discs are employed, one on either side of the fabric of the inflated structure. Silicone caulking is sandwiched between the two discs in the vicinity of a hole which is cut in the fabric of the inflated structure. A threaded eye bolt is inserted through the hole and through corresponding holes in the discs. A nut is threaded onto the eye bolt to compress the two discs, with the silicone caulking and fabric between. The head of the eye bolt extends into the interior of the inflated structure, and is used to suspend the ropes which secure the curtains, nets, lights or the like.
The fabric of an inflated structure is typically coated fabric made of reinforced vinyl sold under the trade-mark SHELTER RITE.TM.. It has been found that silicone caulking will not properly adhere to SHELTER RITE.TM. fabric or to discs made of wood or metal. Consequently, silicone caulking does not form an effective water-tight seal between discs used to sandwich the caulking, and water leaks into the interior of the inflated structure. Further, due to the swaying motion of the inflated structure, it has been found that the discs shift relative to the structure, bringing the threaded portion of the eye bolt into abrasive contact with the fabric of the structure. Again, this results in tearing of the fabric. Often, this system works so poorly that a fabric patch, also made of SHELTER RITE.TM., is resorted to, resulting in the disadvantages of the first system described above. SHELTER RITE.TM. is used as the patch fabric because the patch may be simply welded onto the fabric structure using a hot-air gun and a roller, a technique well known in the art.
Both of the above-described types of suspension devices have to be removed from the fabric structure when the structure is deflated and stored, typically during the summer months. This requires cutting apart any fabric patches so as to remove the discs. New patches must be installed when re-inflating the structure.